The liquid crystal display (LCD), especially TFT-LCD, is researched on the most mature among various technology of flat panel display in the present. The liquid crystal display includes an array substrate designed in the form of a matrix, and a driver IC for the array substrate, in which the display effects are thus attained by the deflection of liquid crystal molecules from changes of electric field in a liquid crystal cell.
With the development of semiconductor technology, dimensions of TFT devices becomes increasingly small, and the requirements for the definition of LCD is becoming increasingly high, thus the widths of the metal wires placed therein are required to be as small as possible. However, under the current technology of manufacturing LCD, a risk of smaller wires is short-circuit or open-circuit failure. In the prior art, the detection rate for short-circuit or open-circuit failures of the array substrate is mostly related to the design of the LCD structure. If both ends of each gate line and that of each data line are open, the detection rate of short-circuit or open-circuit failures can be up to 100%. However, if the common electrode lines of the array substrate are in net-shaped structure, it is hard to detect short-circuit or open circuit failures therein. As shown in FIG. 1, the net is formed by a bus (also referred as to Com bus) 101, and several branches (also referred as to Com line) 102 intersecting with the bus at both ends thereof, and outlet lines as indicated by 103 in FIG. 1. Since the voltage at each point of the common electrode lines connected to form the net is substantially the same, it is easy to neglect these failures, especially open-circuit failures, in the process of manufacturing array substrate, and pass them to the subsequent processes of cell-making and module-making. If not repaired timely, the failures may result in some defects to the display such as horizontal light line in display. During cell-making and module-making, the defect of horizontal light line, once occurs, will be hardly repaired and result in discard or degradation of the product.
It is therefore necessary to provide a solution of effectively detecting short-circuit or open-circuit failures, especially the open-circuit failures, in the process of making array substrates.